SOME FISH TEETH FROM THE KANSAS CRETACEOUS. 



Contribution from the Paleontological Laboratory No. 54, 



BY S. W. WILLISTON. 

 With Plates VI to XIV, inclusive. 



'^^HE following aotes and descriptions of various pycnodont and 

 -^ selachian teeth from the Kan.sas Cretaceous are the result of an 

 endeavor to determine the material in the University Museum which 

 has accumulated in the last ten years, supplemented by a collection 

 kindly loaned me for study by Mr. T. W. Stanton, of the National 

 Museum. The material is by no means exhaustive, nor even sufficient 

 to settle several doubtful points, but I trust that, incomplete as it is, 

 it will be of service for a more thorough study in the future. As a 

 means to this end I have figured fully nearly everything that has been 

 examined. 



"The specific determination of the detached teeth of sharks and 

 skates is little more than guesswork, and to decide upon their generic 

 relationships with any approach to certainty is also often very diffi- 

 cult."* 



Nevertheless, because such detached teeth are so often found, and 

 connected series so very rarely, an attempt at their determination is 

 desirable. Fortunately, in the present collection there are several 

 forms represented by such complete specimens, that the positive ad- 

 dition they afford to the knowledge of the species and genera is very 



welcome. 



PYCNODONTID^. 



The pycnodonts are a peculiar group of ganoid fishes, whose 

 remains have been found in the Jurassic, Cretaceous and Eocene 

 deposits of Europe, North America, Asia, and Australia. They are 

 all rather small fishes, very much flattened and oval in shape, covered 

 with rhomboidal scutes having close-lying spines, which give a ribbed 

 appearance. The united palatine and vomer of the upper jaws are 

 provided with five rows of round or oval, smooth-pavement teeth ; the 

 premaxillary with two or four chisel-like teeth. The dentaries below 

 have a like number of teeth, similar to those of the premaxillary, 



* Woodward: Proe. Geol. Assn., XIII, 190. 



[27J-K.lJ.Qr.— A ix 1-Jan. '00. 



